Field‐induced quantum critical point in the pressure‐induced superconductor CeRhIn₅

Abstract

Abstract When subjected to pressure, the prototypical heavy‐fermion antiferromagnet CeRhIn 5 becomes superconducting, forming a broad dome of superconductivity (SC) centred around 2.35 GPa (= P 2) with maximal T c of 2.3 K. Above the superconducting dome, the normal state shows strange metallic behaviours, including a divergence in the specific heat and a sub‐ T ‐linear electrical resistivity. The discovery of a field‐induced magnetic phase that coexists with SC for a range of pressures P ≤ P 2 has been interpreted as evidence for a quantum phase transition, which could explain the non‐Fermi‐liquid behaviour observed in the normal state. Here we report electrical resistivity measurements of CeRhIn 5 under magnetic field at P 2, where the resistivity is sub‐ T ‐linear for temperatures above T c (or T FL ) and a T 2 ‐coefficient A found below T FL diverges as H c2 is approached. These results are similar to the field‐induced quantum critical compound CeCoIn 5 and confirm the presence of a quantum critical point in the pressure‐induced superconductor CeRhIn 5 . Temperature‐field phase diagram of CeRhIn 5 at 2.35 GPa. magnified image